Which Is Greater: f(-2) or f(10)?

[Sonata4004]

Would you please help me with the question:

The graph of derivative f'(x)= (1/4)x(x-6) is given.
What value is greater f(-2) or f(10)?
It is permitted to sketch f(x) using f'(x) graph, but you can not take the integral of f'(x) directly.

 

[HallsofIvy]

Is that supposed to be f'(x)= (1/4)x(x-6)? The graph of that is a parabola which is symmetric about x= 3. The distance from -2 to 3 is 5 while the distance from 3 to 10 is 7.

 

[Sonata4004]

Thank you for reply,
The graph f(x) is not exactly symmetrical about x=3 since f(-2)=-3.67 while f(8)=-5.33, though the distance from 3 to -2 and 8 is the same.
The data is taken from integral function y=(1/12)x^3-(3/4)x^2.

 

[Sonata4004]

Does anybody have other suggestions? Or maybe some elaboration on the symmetry idea? It is right that f(10)>f(-2), but I don't know solid proof for this unless taking integral, which is out of range of permitted tools